Electric toothbrush

ABSTRACT

An electric toothbrush has a first brush that oscillates and a second brush that oscillates opposite the first brush. The electric toothbrush also has a shaft assembly that includes a moveable pin that creates an oscillating motion of a first brush on a head of the toothbrush. The method of assembly inserts a shaft assembly of the toothbrush through a bottom hole of an elongated hollow body of the toothbrush head to come in contact with a top hole of the elongated body.

BACKGROUND OF THE INVENTION

The present invention relates to an electric toothbrush.

Electric toothbrushes generally employ a moving brush. One goal of the moving brush is to provide a motion that complements the hand action of a user guiding the brush using a handle of the toothbrush. A rotating motion of the moveable brush has been seen to be particularly well suited to complementing the hand motion of the user. Additionally, when using two moveable brushes it has been found that two circular brushes rotating in opposite directions are particularly well suited to complementing the user's hand motion. Therefore, it is an objective of the current invention to employ a rotating moveable brush. Additionally, it is a further objective of the present invention to employ a second rotatable moving brush that moves in a direction opposite the first brush.

In the design of a toothbrush, there is also a need for an accurate and reliable interface between a motor that must be connected to the moveable brushes. In the prior art, this often requires the use of gears or other complex connections. Therefore, a further objective of the present invention is a simple yet efficient connection between the motor and the moveable brushes.

One interconnection between a motor and the moveable brush is seen in McDougall, U.S. Pat. No. 5,625,916. The '916 patent uses a motor in-line with a shaft. The shaft ends with a bend which creates a variety of problems including wear upon a plastic stabilizer point at the head of the toothbrush, assembly complications as the shaft must be fed from a portion of the head to interconnect with a motor at the bottom portion of the head and a wider toothbrush head that must accommodate the bent portion. Therefore, a further objective of the present invention is to provide a shaft structure for a toothbrush that overcomes the difficulties of the prior art.

These and other objectives will become evident from the following specification and claims.

SUMMARY OF THE INVENTION

The foregoing objectives may be achieved by an electric toothbrush having a motor driven head with a first brush and a second brush. The first brush rotating in a first direction with the second brush rotating in a second direction opposite the first direction. A feature of this design may include the first brush oscillating in both the first direction and the second direction with the second brush following the first brush but in an opposite direction.

A further feature of the present invention includes a toothed section on both the first brush and the second brush that reciprocally join the two brushes together.

A further objective of the present invention is an electric toothbrush that connects a motor to a moveable bristle holder with a plurality of tuffs using a rotatable shaft. The rotatable shaft has a longitudinal axis and is operably connected to the motor. A cylindrical cap is attached to the rotatable shaft and has a pin radially offset from the shaft longitudinal axis. The bristle holder has a slot in its outer circumference that engages the pin of the cylindrical cap. Finally, a switch is provided that is operably connected to the motor that when actuated engages the motor causing the bristle holder to oscillate.

A further feature of the present invention is a bushing provided between the rotatable shaft and the cylindrical cap that engages a front portion of the head of the toothbrush but permits rotation of the cylindrical cap through the bushing.

A further feature of the present invention is a gasket between the bushing and the cylindrical cap that prevents water and other debris to enter into the head of the toothbrush.

The foregoing objectives may also be achieved by a method of assembling an electric toothbrush including providing a toothbrush with a handle and a head having an elongated hollow body, a rotatable shaft, a cylindrical cap that may be received upon the rotatable shaft, and a bushing between the rotatable shaft and the cylindrical cap. The method also comprising the step of fitting the bushing upon a rod of the cylindrical cap and the rod within the rotatable shaft, placing the rotatable shaft within the elongated hollow body entering from a bottom opening and the bushing engaging against the top opening. The method also comprising the steps connecting the rotatable shaft to the motor shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of the electric toothbrush of the present invention.

FIG. 2 is an exploded view of the electric toothbrush of FIG. 1.

FIG. 3 is a front view of the head of the present invention illustrating the shaft assembly connected to a moveable brush.

FIG. 4 is an exploded view of the shaft assembly of FIG. 3.

FIGS. 5A-B are illustrations of the operation of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, 10 generally refers to the electric toothbrush of the present invention that comprises a handle 12 and a head 14 joined to the handle. The head 14 has an elongated hollow body 16 and a first interior moveable brush 18 and a second exterior moveable brush 20. The handle 12 has an on-button 22 and an off-button 24 used to control the moveable brushes 18, 20.

As seen in FIG. 2, a motor 26 is provided within the handle 12 that is powered by batteries 28. The batteries 28 are accessible by removing battery cover 30. The motor 26 has extending therefrom a motor shaft 32 that ends in a motor coupling 34.

The head 14 is in axial alignment with the handle 12 along longitudinal axis 36. The head 14 has a shaft assembly 38 that generally has a top end 40 that protrudes out a top end 44 of the elongated body 16. The shaft assembly 38 also has a bottom end 42 that is adjacent the elongated body bottom end 46. The shaft assembly bottom end 42 attaches to the motor coupling 34. The motor coupling 34 and shaft assembly bottom end 42 may be interchangeably male or female members. A gasket 49 is provided at the interface between the handle 12 and the elongated body 16.

As seen in FIGS. 3 and 4, the shaft assembly 38 has a shaft 48 having a bottom end 50 and a top end 52. The shaft top end 52 has a hollow 54 defined therein for connecting to a cylindrical cap 56. The cylindrical cap 56 has a rod 58 extending from a bottom end of the cap 56 and a radially offset pin 60 extending from the top end of the cylindrical cap 56. The pin 60 may end in a spherical ball 62. The pin 60 has a longitudinal axis 64 that is offset from the shaft assembly longitudinal axis 36. A bushing 66 and gasket 68 are also provided with the shaft assembly 38.

The shaft assembly 38 is connected together by placing gasket 68 first upon rod 58 and then sliding the bushing 66 upon the rod 58. The rod 58 is then placed into the hollow 54 of the shaft 48.

The pin 62 is connected to the first brush 18. The brush 18 has a generally circular bristle holder 70 having a plurality of tufts 72. The bristle holder 70 has a rectangular slot 74 that extends radially inward into the bristle holder 70. The rectangular slot 74 is configured to permit the pin 62 to move up and down through it as it rotates about a circle, thus moving the bristle holder 70 in an oscillating, side-to-side motion about its pivot point 77. Brush 18 has a first toothed section 78 along its outer circumference. The first toothed section 78, as illustrated, is opposite and centered upon the rectangular slot 74.

The first toothed section 78 drives a second brush 20. The second brush 20 has a second bristle holder 80 and second tufts 82. The second brush 20 has an oscillating motion 86 opposite the oscillating motion 76 of the first brush 18 as it turns about its pivot point 87. Motion from the first brush is translated to the second brush from the first tooth section 78 to a second tooth section 90.

The geometry of the first tooth section 78 and the second tooth section 90 may vary relative the circumference of the first brush 18 and second brush 20, respectively. As best seen in FIGS. 3, 5A and 5B the second tooth section 90 is slightly more inset than the first tooth section 78.

As seen in FIGS. 5A and 5B in operation, the motor 26 creates a rotational movement of motor shaft 32 which moves shaft assembly 38 having pin 60. The pin 60 moves up and down within rectangular shaft slot 74 to create oscillating motion 76. An opposite oscillating motion 86 results from the reciprocal interconnection between the first and second toothed sections 78, 90.

Also unique to the present invention is the method of assembling the shaft assembly 38 within the elongated hollow body 16. As stated previously, the elongated hollow body 16 has a top open end 44 and a bottom open end 46. Once the shaft assembly 38 is assembled it may be placed within the bottom open end 46 into the elongated hollow body 16 until the bushing 66 comes to rest within the top open end 44. In this position, the shaft 48 and the cylindrical cap freely rotate within the bushing 66 that is held adjacent the top open end 44.

The drawings and specification there has been set forth a preferred embodiment of the invention, and those specific terms are employed, their use is in a generic descriptive sense only and not for purposes of limitation. Changes in the form and the proportion of parts as well as in the substitution of equipment are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of the invention in the following claims. For example, the present invention contemplates variations in the shaft assembly, the size and positioning of the first brush and the second brush, the number of brushes used, the interface between the first brush and the second brush, variations in the cylindrical cap, and other variations in structural and function. 

1. An electric toothbrush comprising: a handle having a motor disposed therein; a head joined to the handle; a first brush pivotally mounted to the head having a generally circular first bristle holder with a first outer circumference; a second brush pivotally mounted to the head having a generally circular second bristle holder with a second outer circumference; the first brush interconnected to the second brush; a rotatable assembly connected to the motor and the first brush; a switch operably connected to the motor, wherein said switch is actuated to engage the motor thereby causing the assembly to turn, the first brush to rotate in a first direction, and the second brush to rotate in a second direction opposite the first direction.
 2. The electric toothbrush of claim 1 further comprising a first toothed section upon the first outer circumference, a second toothed section upon the second outer circumference, wherein the first brush is interconnected to the second brush by reciprocally joining the first and second toothed sections.
 3. The electric toothbrush of claim 2 wherein the toothed sections are on a portion of the outer circumference.
 4. The electric toothbrush of claim 1 wherein the first brush is interior of the second brush.
 5. The electric toothbrush of claim 1 wherein the first brush is larger than the second brush.
 6. The electric toothbrush of claim 1 further comprising a pin radially offset from an assembly longitudinal axis, a rectangular slot upon the first bristle holder that extends radially inward from the first outer circumference, wherein the pin engages the rectangular slot throughout rotational movement of the pin causing the first brush to oscillate.
 7. An electric toothbrush comprising: a handle having a motor disposed therein; a head joined to the handle, the head having a pivotally mounted bristle holder with a plurality of tufts; a rotatable assembly having a longitudinal axis and operably connected to the motor, the assembly extending from the handle to the head; the assembly having a shaft and cylindrical cap; the cylindrical cap having a pin radially offset from the longitudinal axis; the bristle holder having a slot extending radially inward from the outer circumference to engage the pin of the cylindrical cap; a switch operably connected to the motor, wherein said switch is actuated to engage the motor thereby causing the bristle holder to oscillate.
 8. The electric toothbrush of claim 7 wherein the pin extends from the cap and ends in a spherically member.
 9. The electric toothbrush of claim 7 wherein the bristle holder is generally circular.
 10. The electric toothbrush of claim 7 wherein the rotatable shaft is made of a polymeric material.
 11. The electric toothbrush of claim 7 wherein the cylindrical cap is metal.
 12. The electric toothbrush of claim 6 wherein the pin has a longitudinal axis approximately parallel the shaft longitudinal axis.
 13. The electric toothbrush of claim 7 further comprising a bushing between the rotatable shaft and the cylindrical cap, the bushing engaging the head but permitting rotation of the cylindrical cap.
 14. The electric toothbrush of claim 7 further comprising a gasket between the bushing and the cylindrical cap.
 15. An electric toothbrush comprising: a handle at a first end of the toothbrush having a motor disposed therein; a head at a second end of the toothbrush, the head having pivotally mounted interior and exterior bristle holders each with a plurality of tufts; the interior bristle holder being generally circular with a first outer circumference and a first toothed section upon the first outer circumference; the exterior bristle holder being generally circular with a second outer circumference and a second toothed section upon the second outer circumference; the interior bristle holder interconnected to the exterior bristle holder by reciprocally joining the first and second toothed sections; a rotatable assembly having a longitudinal axis operably connected to the motor, the assembly extending from the handle to the head; the assembly ending in a member radially offset from the longitudinal axis; the interior bristle holder having a rectangular slot extending radially inward from the first outer circumference to engage the pin throughout rotational movement of the pin; a switch operably connected to the motor, wherein said switch is actuated to engage the motor thereby causing the interior bristle holder to rotate in a first direction and the exterior bristle holder to rotate in an opposite second direction.
 16. The electric toothbrush of claim 15 wherein the rectangular slot is approximately centered upon the first toothed section.
 17. The electric toothbrush of claim 15 wherein the first outer circumference is larger than the second outer circumference.
 18. A method of assembling a toothbrush including: providing a toothbrush comprising: (a) a handle having a motor disposed within, a motor shaft extending from the motor; (b) a head having at least one brush pivotally attached and an elongated hollow body adjacent the brush with a bottom opening and a top opening; (c) a shaft assembly having a shaft and cylindrical cap; (d) the shaft having a first end for matingly engaging the motor shaft and a second end; (e) a cylindrical cap having a rod extending from one end and a pin on an opposite end; (f) a bushing for placement upon the rod; fitting the bushing upon the rod and the rod within the shaft second end; placing the shaft assembly within the elongated hollow body entering from the bottom opening, engaging the bushing against the top opening, and coupling the pin to the brush; connecting the rotatable assembly shaft first end to the motor shaft. 